A Partial-Current-Steering Biphasic Stimulation Driver for Vestibular Prostheses

Constandinou, Timothy G.; Georgiou, Julius; Toumazou, C.

doi:10.1109/tbcas.2008.927238

Cited by 71 publications

(33 citation statements)

References 32 publications

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“…The parallel H-bridge arrangement enables a single current sink to selectively pull current through any of the 8 channels, however, this does mean that only a single channel can be active at any moment in time. It is envisaged that the end application will target electrode sites at close proximity and therefore a Continuous Interleave Strategy (CIS) [32], [33] will be used to avoid any cross-stimulation.…”

Section: H-bridgementioning

confidence: 99%

An energy-efficient, dynamic voltage scaling neural stimulator for a proprioceptive prosthesis

Williams

Constandinou

2012

2012 IEEE International Symposium on Circuits and Systems

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Abstract-This paper presents an 8 channel energy-efficient neural stimulator for generating charge-balanced asymmetric pulses. Power consumption is reduced by implementing a fullyintegrated DC-DC converter that uses a reconfigurable switched capacitor topology to provide 4 output voltages for Dynamic Voltage Scaling (DVS). DC conversion efficiencies of up to 82 % are achieved using integrated capacitances of under 1 nF and the DVS approach offers power savings of up to 50 % compared to the front end of a typical current controlled neural stimulator. A novel charge balancing method is implemented which has a low level of accuracy on a single pulse and a much higher accuracy over a series of pulses. The method used is robust to process and component variation and does not require any initial or ongoing calibration. Measured results indicate that the charge imbalance is typically between 0.05 % -0.15 % of charge injected for a series of pulses. Ex-vivo experiments demonstrate the viability in using this circuit for neural activation. The circuit has been implemented in a commercially-available 0.18 μm HV CMOS technology and occupies a core die area of approximately 2.8 mm 2 for an 8 channel implementation.

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Section: H-bridgementioning

confidence: 99%

An energy-efficient, dynamic voltage scaling neural stimulator for a proprioceptive prosthesis

Williams

Constandinou

2012

2012 IEEE International Symposium on Circuits and Systems

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“…3) Inter-phasic Delay: A short delay is introduced between the cathodic and anodic phases to avoid blocking the propagation of the AP recruited [3]. SW 1 is set open to break both paths.…”

Section: B Detailed Sequencementioning

confidence: 99%

“…Each Single Pole, Double Throw (SPDT) switch (SW 2,3,6 ) is implemented using two transmission gates. Switch charge injection is not expected as a challenge because: (1) transmission gates significantly reduce any switch-related charge injection; (2) the symmetry between switches in Path 1 and Path 2 ensures any injected charge is recycled; (3) all switches are present within the stimulation path, any charge injection is metered and therefore eliminated.…”

Section: A Switch Designmentioning

confidence: 99%

“…The charge is delivered through electrodes positioned in close proximity to the target site (neuron somas or neural tissue) using one of three typical methods: Current-Mode Stimulation (CMS) [3], Voltage-Mode Stimulation (VMS) and Charge-Mode Stimulation (ChgMS) [4]. In CMS, the charge is delivered by a constant current source with its quantity being controlled easily by setting the duration, but a voltage headroom must be maintained to ensure the output transistor is in saturation.…”

Section: Introductionmentioning

confidence: 99%

“…Fig. 1 shows a typical waveform in CMS [3], [6]. In practice it is challenging to achieve a perfectly balanced biphasic delivery due to circuit non-idealities such as mismatch and nonlinearities.…”

Section: Introductionmentioning

confidence: 99%

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A novel charge-metering method for voltage mode neural stimulation

Luan

Constandinou

2012

2012 IEEE International Symposium on Circuits and Systems

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Abstract-This paper presents a novel, fully-integrated circuit for achieving change-balanced voltage-mode neural stimulation based on a charge-metering technique. The proposed system uses two small on-chip capacitors, a counter, two comparators and a control-logic circuit to measure the charge delivered to the tissue. This has been designed to deliver a maximum charge stimulus of 10.24 nC within 100 µs. Simulated results show a charge delivery error of 0.4-4% and a maximum residual charge of −73 pC. Implemented in 0.18 µm CMOS, the total power consumption is 42 µW.

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Progress Toward Development of a Multichannel Vestibular Prosthesis for Treatment of Bilateral Vestibular Deficiency

Fridman

Santina

2012

The Anatomical Record

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This article reviews vestibular pathology and the requirements and progress made in the design and construction of a vestibular prosthesis. Bilateral loss of vestibular sensation is disabling. When vestibular hair cells are injured by ototoxic medications or other insults to the labyrinth, the resulting loss of sensory input disrupts vestibulo-ocular reflexes (VORs) and vestibulo-spinal reflexes that normally stabilize the eyes and body. Affected individuals suffer poor vision during head movement, postural instability, chronic disequilibrium, and cognitive distraction. Although most individuals with residual sensation compensate for their loss over time, others fail to do so and have no adequate treatment options. A vestibular prosthesis analogous to cochlear implants but designed to modulate vestibular nerve activity during head movement should improve quality of life for these chronically dizzy individuals. We describe the impact of bilateral loss of vestibular sensation, animal studies supporting feasibility of prosthetic vestibular stimulation, the current status of multichannel vestibular sensory replacement prosthesis development, and challenges to successfully realizing this approach in clinical practice. In bilaterally vestibular-deficient rodents and rhesus monkeys, the Johns Hopkins multichannel vestibular prosthesis (MVP) partially restores the three-dimensional (3D) VOR for head rotations about any axis. Attempts at prosthetic vestibular stimulation of humans have not yet included the 3D eye movement assays necessary to accurately evaluate VOR alignment, but these initial forays have revealed responses that are otherwise comparable to observations in animals. Current efforts now focus on refining electrode design and surgical technique to enhance stimulus selectivity and preserve cochlear function, optimizing stimulus protocols to improve dynamic range and reduce excitation–inhibition asymmetry, and adapting laboratory MVP prototypes into devices appropriate for use in clinical trials.

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A Partial-Current-Steering Biphasic Stimulation Driver for Vestibular Prostheses

Cited by 71 publications

References 32 publications

An energy-efficient, dynamic voltage scaling neural stimulator for a proprioceptive prosthesis

An energy-efficient, dynamic voltage scaling neural stimulator for a proprioceptive prosthesis

A novel charge-metering method for voltage mode neural stimulation

Progress Toward Development of a Multichannel Vestibular Prosthesis for Treatment of Bilateral Vestibular Deficiency

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